Process of producing low-carbon ferro-alloys.



ployed to produce these alloys.

usually produced by combustion but readily- To all whom it may concern:

tungsten, titanium, vanadium or nickel, is cheaply produced by smelting a mixture of;

.Bessemer process of .producing steel, the;

molten pig-iron containing a .small amountp AT Flt),

JOHN M. MOREHEAD, 02E CHICAGO, ILLINOIS, ASSIGNOR T0 ELECTED METALLURGICAL COMPANY, OIFOHICAGO, ILLINOIS, A CORPORATION.0iF WEST VIRGINIA.

N0 Drawing.

Be it known that I, JOHN M. MOREHEAD, a citizen of the United States, residing at Chicago, in the county of Cook .and State of Illinois, have invented certain new and useful Improvements in Processes of Producing Low-Carbon F erro-Alloys, of which the following is .a specification.

The value of the ferro-alloys commonly employed as a means of introducing chromium, vanadium and other metals into special steels, is largely dependent on a low carbon content, and methods of reduction involving the use of expensive metallic reducing agents, or giving low yields, are em- The present process of producing lowcarbon ferro-alloys comprises two stages.

In the first stage, a high-carbon ferro-alloy,

for example one of chromium, molybdenunn' an ore of the alloying metal, an excess of carbon and a source of iron. The reduction may be effected in an ordinary electric furnace having a carbon lining and depending carbon electrodes. In the second stage, the; carbon is removed or reduced to a small per i .centage by heating the molten alloy to ag temperature such that the afiinity of oxygen? for the contained carbon is greater than itsi affinity for the chromium or other alloyedi metal, and then subjecting it for .a limited, period to the action of oxygen, air treated? to alter'its oxygen content, or a gas or vapor containing combined oxygen, for example an oxide of carbon, or steam. In the ordinary of silicon or' other highly-positive metal and 5 carbon is subjected to the action of air at} temperatures such that the affinity of oxygen! for the silicon or other alloyed positive metal is greater than its affinity for carbornso that g the removal, of the alloyed metalflsubstan j 'tially precedesthe removal of carbon. But

when the temperature of one of the specified alloys .of iron, ahighly-positive metal land carbon, is raised to a temperature above that employed in the Bessemer steel industry or obtainable in an electric furnace, for example a temperature between 1600 C. and

Specification of Letters latent.

I IPBOCESS OF PRODUCING LOW-CARBON FERRO-ALLOYS.

Patented June 3, 1913.

Application filed September 24, 1907. Serial No. 394,273.

the heat of combination of the carbon and oxygen becomes greater than the heat of combination of the alloyed metal and oxygen, and the carbon may then be largely or substantially eliminated by oxidation before any considerable percentage of the alloyed metal is removed.

' In carrying out the second stage of the process, the ferro-alloy high in carbon may be subjected to' the action of oxygen or a gas or vapor containing combined oxygen in the electric furnace in which it has been produced, as by providing the lower end of the furnace with openings and forcing the gas through these openings and through the molten alloy. Or the alloy may be tapped from the electric reduction furnace, at a high temperature, into a separate vessel, and therein treated with the gas, more heat being supplied if necessary, either by an are, or by passing an electric current through the alloy, acting as a resistor, or through a slag or other resistor in contact with or proximity to the alloy. Or the cast alloy may be remelted and electrically heated to the requisite temperature. The gas may either be forced through the alloy or caused to act upon its surface, as in the present art of bessemerizing pig-iron.

The term ferro-alloys, as used in the claims, means a product in which the metal alloyed with iron is the important and valuable constituent, as distinguished from pigiron, which may contain one or two per cent. of silicon and manganese.

The Word oxygen, as used in certain claims, is intended to mean either pure or substantially pure oxygen, or air treatedto alter, its oxygen content, or a gas or vapor containing combined oxygen.

I claim: v

-1. The process of producing low-carbon ferro-alloys, which consists in first producing a ferro-alloy high in carbon, and then subjecting the product, heated to a temperaturesuch that the aflinity of oxygen for the contained carbon is greater than its aflinity for the alloyed metal, to the action of gaseous oxygen.

'2. The process of'producing low carbon ferro-alloys, which consists in first producing a ferro-alloy high in carbon, and then subjecting the product, electrically heated to a temperature such that the affinity of oxygen for the contained carbon is greater than its aflinity for the alloyed metal, to the action of gaseous oxygen.

3. The process of producing low-carbon ferro-alloys, which consists in electrically smelting a compound of the alloying metal, an excess of carbon and a source of iron, and subjecting the high-carbon product, electrically heated to a temperature such that the affinity of oxygen for the contained carbon is greater than its affinity for the alloyed metal, to the action of gaseous oxygen.

'4. The process of producing low-carbon ferro-alloys, which consists in first producing a ferro-alloy high in carbon, and then subjecting the product, heated to a temperature such that the aflinity of oxygen for the contained carbon is greater than its affinity for the alloyed metal, to the action of an oxidizing gas containing combined oxygen.

'5. The process of prooucmg low-carbon ferro-alloys, which consists in first producin a ferro-alloy hir h in carbon, and then subjecting the product, electrically heated to a temperature such that the aflinity of oxygen for the contained carbon is greater than its aflinityfor the alloyed metal, to the action of an oxidizing gas containing combinedoxygen.

6. The process of producing low-carbon ferro-alloys, which consists in electrically smelting a compound of the alloying metal, an excess of carbon and a source of iron, and subjecting the high-carbon product, electrically heated to a temperature such that the affinity of oxygen for the contained carbon is greater than its afiinity for the alloyed metal, to the action of an oxidizing gas containing combined oxygen.

7. The process of producing low-carbon ferrochromium, which consists in first producing ferrochromium high in carbon, and then subjecting the product, heated to a temperature such that the affinity of oxygen for the contained carbon is greater than its. aflinity for chromium, to the action of gasej ous oxygen.

8.'The process of producing low-carbon. ferrochromium, which consists in first pro.- ducing ferrochromium high in carbon, and; then subjecting the product, electrically heated to a temperature such that thej affinity of oxygen for the contained carbon is greater than its aflinity for chromium, to the action of gaseous oxygen.

9. The process of producing low-carbonferrochromium, which consists in electrically smelting a compound of chromium, an excess of carbon and a source of iron, and subjecting. the high-carbon product, electrically heated to a temperature such that the affinity of oxygen for the contained carbon is greater than its aflinity for chromium, to the action of gaseous oxygen.

10. The process of producing low-carbon ferrochromium, which consists in first producing ferrochromium high in carbon, and then subjecting the product, heated to a temnerature such that the affinity of oxygen for the contained carbon is greater than its aflinity for chromium, to the action of an oxidizing gas containing combined oxygen.

11'. The process of producing low-carbon ferrochromium, which consists in first producing ferrochromium high in carbon, and then subjecting the product, electrically heated to a temperature such that the .affinity of oxygen for-the contained carbon is greater than its affinity for chromium, to the action ofan oxidizing gas contammg combined oxygen.

12. The process of producing low-carbon ferrochromium, which consists inelectrically smeltmg a compound. of chromlum, an excess of carbon and a source of H011, and

subjecting the high-carbon product, e'lectrically heated to a temperature such that the aflinityof oxygen for the contained carbon is greater than its affinity for chromium, to the action of an oxidizing gas containing combined oxygen.

13. The process of producin low-carbon ferro-alloys, which consists in first producing a ferro-alloy high in carbon, and then subjecting the product, heated to a temperature above 1600" (l, to the action of oxygen.

14. In a process of refining metals and alloys, the steps consisting in maintaining a molten bath containing free metal and slag at an elevated temperature in a refining chamber by passing therethrough an electric heating current, and subjecting said metal to the action of an oxidizing gas having more than one equivalent of oxygen to effect selective oxidation in said molten metal.

In testimony whereof, I affix my signature in presence of two witnesses.

JOHN M, MOREHEAD. lVitnesses: L

E. F. PRICE,

F. E. LAWTON. 

